х(х-4)=(х+3)
x² - 4x = x + 3
x² - 4x - x - 3 = 0
x² - 5x - 3 = 0
a=1, b=-5, c=-3
D = b² - 4ac = (-5)² - 4*1*(-3) = 25 + 12 = 37;
D > 0
x1 = -b+√D/2a = 5+√37/2;
x2 = -b-√D/2a = 5-√37/2;
Ответ : 5+√37/2; 5-√37/2;
Если (х+3)² то
х(х-4)=(х+3)²
x² - 4x = x² + 6x + 9
x² - x² -4x - 6x - 9 = 0
-10x - 9 = 0 | : (-1)
10x + 9 = 0
10x = -9
x = -9/10 = -0,9
Ответ : -0,9